Jeremiah Horrocks, William Crabtree, and the Lancashire observations of the transit of Venus of 1639

摘要

When Jeremiah Horrocks correctly predicted, and with his friend William Crabtree observed, the Venus transit of 24 November 1639, these two men became more than the first astionomers in history to witness a rare celestial phenomenon For Horrocks's and Crabtree's achievement constituted in may ways the first major astronomical discovery to be made in Renaissance England It is also clear from their writings, moreover, that the two men, working in the isolation of rural Lancashire and well away from London or the universities, were fully conversant with contemporary discoveries made in continental Europe by Tycho Brahe, Galileo, Kepler, Gassendi, and others. In many ways, therefore, their work begs more questions than can easily be answered, such as why the rural North-West produced not only Horrocks and Crabtree, but other contemporary astronomers such as the Lancastrians Charles Towneley, Jeremy Shakerley, and their Yorkshire friend William Gascoigne Yet in addition to whatever regional circumstances might have been present, and how easy it might have been for an educated rural Lancastrian to be fully informed about what astronomers in Paris, Prague, or Florence were doing, what cannot be denied is the outstanding originality of their wider achievement. For Jeremiah Horrocks in particular was a physical scientist of genius. His correct determination of the elliptical shape of the lunar orbit by 1638 when he was about 20 and his wider work on planetary dynamics place him amongst the most creative researchers of the seventeenth century. Central to Horrocks's and Crabtree's achievement was Crabtree's realisation by 1636 that contemporary published astronomical tables were unreliable, and that if one wanted to do serious work in understanding the heavens, then one had to observe and measure them for oneself, and learn to draw original conclusions.